The present invention relates to fluid flow meters having an annular rotor operating in a vortex chamber.
The present invention is particularly useful in the context of vortex flowmeters including a rotor that rotates without contact with other components. This operation is useful in applications in which rotor bearing drag can affect resolution or accuracy. Rotation of the rotor is sensed by transducer means.
In a vortex chamber flow meter, liquid flows into a meter housing. Within the housing is a component which may be described as a jet ring having a central cylindrical operating chamber therein. An annular rotor in the chamber is centrally positioned in operation by vortex flow. Liquid enters the jet ring through a plurality of ports each communicating with a conduit extending through the cylindrical wall of the jet ring. Conduits each direct flow into the chamber tangentially with respect to the rotor. Liquid exits axially from an aperture at the center of the chamber. The rotor rotates free of contact with the chamber, and rotation is monitored by transducer means such as optical sensing means responsive to movement of index marks on a surface of the rotor. The ports are equiangularly positioned around the periphery of the chamber.
Such a design has been successfully employed and has been considered to be satisfactory. It was not readily apparent to those skilled in the art that this operation could be improved upon.